Three current and former Auto Club of Southern California employees have filed a lawsuit claiming the nonprofit insurance federation has violated state law since at least 1995 by failing to pay overtime wages to 650 sales employees. The suit, filed in Los Angeles County Superior Court, seeks class-action status. The plaintiffs claim that the sales agents, who sold auto, homeowner and life insurance in addition to club memberships, worked 50 to 70 hours per week but received no overtime pay and that they were "misclassified" as exempt when they should have been nonexempt. The Auto Club, which is the largest affiliate of the American Automobile Assn., denied that it wrongly classified its agents. "We believe we have a professional, commissioned sales force which is exempt, not a time-card sales force which would not be exempt," said Carol Thorp, auto club spokeswoman. The suit, which did not specify monetary damages, seeks an injunction to force overtime payments.